Fix MinGW STL compile error

If namespace std is using namespace tr1 prior to inclusion of any STL
headers, the MinGW STL complains of an ambiguous namespace __detail,
which could be either std::__detail or std::tr1::__detail.  This fix
avoids the error because it does not alter the std namespace, it simply
includes both std and std::tr1 within the stl namespace.

NOTE: I have forcibly converted all CRLF pairs to LF, which resulted in
several strange lines in the diff where the text is otherwise identical.